Pluripotency determining factors are described which act intracellularly and maintain a pluripotent cell in a pluripotent state in the absence of gp130 activation, which maintain or confer pluripotency of a human stem cell, which maintain or confer pluripotency of a mouse ES cell, and which maintain or confer pluripotency of a stem cell from a non-permissive strain of mice. The factors and vectors encoding or activating the factors are used to maintain and derive pluripotent cells, especially of higher mammals, including humans.